An article storage case molded of a plastic or a like material is adopted for storage, safekeeping and transportation of parts in a factory or the like.
Among such article storage cases, one known article storage case is of the type provided with coupling means configured to couple such cases to each other in order to prevent fall or collapse of a load of such cases placed side by side on a pallet or a like inconvenience in transportation by a forklift.
An article storage case (plastic container) disclosed in Japanese Patent Application Laid-open No. H7-52950 (hereinafter will be referred to as “Patent Document 1”) for example has a side surface fitted with a permanent magnet which serves as coupling means for coupling adjacent cases to each other by the magnetic force of the magnet.
An article storage case (container) disclosed in Japanese Patent Application Laid-open No. H9-169339 (hereinafter will be referred to as “Patent Document 2”) has an opening edge portion in an upper portion thereof which is fitted with a pivotable coupling member of steel configured to engage the upper edge and/or the coupling member of a counterpart case placed adjacent thereto by pivoting.
Any one of the cases described in Patent Documents 1 and 2 noted above, however, has to be fitted on its case body with the permanent magnet or coupling member as a separate part. Such a separate part incurs an increase in cost by the price thereof. In recycling the case, the permanent magnet or coupling member thus fitted has to be removed, which is inconvenient.
Though the case described in Patent Document 1 utilizes the magnetic force of the permanent magnet to allow a stable stack of such cases to be formed with less possibility of falling or collapsing by simply placing the cases side by side, the coupling force between adjacent cases is weak and, hence, the coupling therebetween is poor in reliability. In addition, since only the magnetic coupling force between adjacent cases is utilized, a forklift or the like cannot transport the cases thus coupled without using a pallet.
On the other hand, the technique disclosed in Patent Document 2 enables highly reliable coupling to be made between cases by means of the coupling member of steel. However, a troublesome coupling operation using the coupling member is indispensable.